hi pusparaga
its frequency range is 0.3Ghz~300Ghz,contains meter wave,decimetric wave,centimeter wave and millimeter wave,namely ,the wavelength is from one millimeter to one meter.
It's just a quirk of language, we use the terms 'long wave', 'medium wave', 'short wave' then for some reason lost to history we tend to use frequency terms for VHF and UHF then revert to wave lengths again, 'micro' just meaning 'small'. It is quite common to see references to 'millimetre wave' though.
Sir,
Some books, I read it microwave frequency range is 1GHz to 1000GHz. In the posting #2, he said it microwave frequency range is 0.3GHz to 300GHz. I heard it RF frequency is 20 MHz to 1GHz. Which range is correct, in many books also they said in ambiguity in the range, which one is correct.
Microwaves were mathematically predicted by Maxwell.
After all radio experiments done at low frequencies by Hertz, Marconi, Tesla, Braun, Popov, and many others, there was J.C. Bose who made the first transmitter/receiver working on the microwave frequencies. Also he was the first to name those waves, "microwaves" due to their very low wavelength.